Paper machine breast roll



Jan. 23, 1962 J. L; PEDRICK PAPER MACHINE BREAST ROLL Filed Sept. 26, 1956 BY uh 3,017,928 PAPER MACHINE BREAST ROLL John L. Pedrick, Milrnont Park, Pan, assignor to Scott Paper-Company, Chester, Pa., a corporation of Pennsylvania Filed Sept. 25, 1956, er. No. 612,178 3 Claims. (Cl. Mil-28?) The present invention relates to the art of paper making and more specifically relates to the machinery for producing lightweight tissue paper at high speeds. Even more specifically the present invention concerns the construction of a breast roll on a Fourdrinier machine.

With the advances in the art of paper making, the development of high speed machinery, and particularly Fourdrinier machines, has reached the point where it is not uncommon to find apparatus forming webs'of paper 200 to 300 inches wide at speeds of half a mile a minute. These high speed machines are exceedingly complex and the various elements now fall into separate and distinct classes of art.

Thus, we find that breast rolls are distinguished from press rolls and from calendar rolls and from dandy rolls, etc., and even the breast rolls are now sub-classified as solid or grilled and, in fact, even the grilled breast rolls are further sub-divided into those which operate with suction and those which operate without suction. Typical of a suction operated grilled breast roll is the apparatus disclosed in Ostertag Patent No. 2,418,600.

'However, not all paper making machines can make use of grilled breast rolls and even fewer operate fast enough to require suction operated grilled breast rolls. Those which can utilize grilled breast rolls, either with or without suction, almost without exception operate at higher speeds than do the Fourdrinier machines utilizing a solid roll. i

Prior inventors have described machines utilizing grilled rolls and have discoursed at length on the efiiciency and desirability of utilizing grilled rolls. However, all prior inventors in this field utilized a structure which included a cover wire supported by a framework including axial-extending bars which, in effect, divided the surface of the breast roll into myriad pockets or cells, giving the surface of the roll the appearance of a honeycomb. These bars had a particularly undesirable effect on the paper because they caused changes in the density of the paper known in the trade as bar-marks. Such bar-marks thus cause non-uniform paper to be formed and paper manufacturers have long sought to eliminate such undesirable conditions.

I have found that the bar-marks are created by the stock striking the axial-extending supports or bars after passing from the slice through the Fourdrinier wire then through th cover wire on the breast roll. If the peripheral speed of the roll exceeds the linear speed of the stock, then centrifugal force will throw the stock forwardly and upwardly radially outwardly against the under side of the stock mat which has been deposited on the wire, disrupting formation of the web, and thus causing bar-marks. If the peripheral speed of the roll is less than the linear speed of the stock, the stock strikes the bars after passing through the Fourdrinier wire and the cover wire and is deflected or splashed back against the under side of the mat of stock on the wire, thus also causing bar-marks.

States Patet It is only when the stock flow is controlled so nicely that its rate of flow is exactly equal to the linear speed of the roll that no bar-marks occur. Of course, any paper manufacturer realizes the difficulty of exactly maintaining in synchronism the rate of stock flow and the linear speed of the roll and for the first time I have discovered that the cover wire on the roll may be adequately and eifectively supported without utilizing axialextending bars therebeneath. I have developed a breast roll which does not have the honey-combed or grilled surface of previous rolls and which eliminates any barmarks on the paper, regardless of whether or not the stock and roll speed are in synchronism.

With the foregoing in mind, one object of the present invention is to provide a breast roll for a Fourdrinier machine, which breast roll, when installed and operating in a machine creates no bar-marks in the paper web.

Another object of the present invention is to provide a breast roll for Fourdrinier machines which is constructed and arranged particularly for use with a pressure inlet or slice and which prevents any throw back of water against the underside of the newly formed paper web as it is carried away from the breast roll on the Fourdrinier wire.

Another object of the present invention is to reduce the cost of manufacture and maintenance of peripherally vertical rolls for carrying a travelling wire in paper making operations.

Another object of the present invention is to provide a new and improved support for the cover wire on the breast roll of a Fourdinier machine.

Still another object of the present invention is to eliminate the formation of bar-marks in paper webs produced on a Fourdrinier machine.

Further objects will be apparent by reference to the appended specification, claims and drawings.

For the purpose of illustrating the invention, there is shown in the accompanying drawings forms thereof which are at present preferred, although it is to be understood that the various instrumentalities of which the invention consists can be variously arranged and organized and that the invention is not limited to the precise arrangements and organization of the instrumentalities as herein shown and described.

In the drawings wherein like reference characters indicate like parts:

FIGURE 1 represents a front elevational view, partly in section, of a breast roll incorporating the present invention.

FIGURE 2 represents a vertical cross-sectional view of the breast roll of FIGURE 1, with the top lip and bottom lip of a typical slice installation illustrated therewith and showing the discharge of the stock from the slice through the wire into the open periphery of the breast roll.

FIGURE 3 is a fragmentary vertical cross-sectional view, on an enlarged scale, of one form of fin construction for supporting the cover wire on the breast roll.

FIGURE 4 is a fragmentary vertical cross-sectional view similar to FIGURE 3 illustrating the use of drilled holes in the shell between the base of the fins for providing a breast roll specifically adapted for utilization with suction boxes disposed within the interior of the breast roll.

FIGURE 5 .is a fragmentary front elevational view,

partly in section, of a breast roll which shows another embodiment of the present invention illustrating an optional form of incorporating radially-extending fins on the surface of the roll for supporting the cover wire in spaced relationship to the exterior of the shell.

With reference to the drawings and particularly to FIGURE 2, the present invention can be more clearly comprehended by considering the relatively thick shell 20 of the breast roll which is supported for rotation on a horizontal axis in the manner well-known to those skilled in the art. This shell 20 may be a solid member (when no suction is utilized in the operation of the breast roll) or may be drilled with a multitude of radially-extending holes. The drilled roll is illustrated in FIGURE 4 and is used when a suction box (not shown) is disposed within the breast roll for drawing the stock water more rap idly and efiiciently through the cover wire and travelling wire directly beneath the slice opening.

The customary or usual Fourdrinier wire 21 is trained about the breast roll, and a slice 22,including top lip 23 and bottom lip 24. The top lip is disposed directly above the wire 21 very near the vertical center line of the breast roll and the edge of the bottom lip 24 is disposed substantially behind the vertical center line of the breast roll so that the stock is discharged against the wire 21 while it still finds support on the breast roll.

In breast rolls of the type under consideration herein the wire 21 does not travel in direct contact with the exterior surface of the shell 20 but is spaced radially therefrom. In the present invention the breast roll is constructed and arranged so that the wire 21 contacts a cover Wire 25 which rests upon the outer edge of a plurality of fins 26. Cover wire 25 is generally a cylindrical sleeve and the fins 26 keep it concentrically spaced with respect to the outer surface of the shell 20.

Because the cover wire 25 is the support for the wire 21, it must be relatively unyielding so that the stock 27 (which travels at substantially the same rate of speed as the wire and thus impinges against the wire with considerable force), does not cause the wire 21 to be depressed away from the edge of the upper lip 23. If such conditions were to exist the formation of the stock on the wire would be uneven and an imperfectly formed web would result. Hence the cover wire 25 may be formed of a 10 x 14 wire mesh with each wire being in the magnitude of .028 in diameter. Nevertheless sup port for such cover wire must also be adequate to prevent defiection of the cover wire or the travelling Fourdrinier wire and, to that end, I provide the plurality of radially-extending fins 26.

In the embodiment shown in FIGURES 3 and 4 the fins are generally trapezoidal in cross-section with the side walls 28 being disposed symmetrically with respect to a vertical center line. The outer edges of the fins are preferably truncated so that a fiat surface or land is provided against which the cover wire may rest. It is noted that the base of the fins is substantially wider than the fin at its outer edge, to provide a relatively rigid member which will not deflect under the impact of the stock against the cover wire supported on its outer edge.

Although I prefer to use a number of identical, closely spaced, annular fins, I have found satisfactory construction in a breast roll wherein a single continuous fin is formed spirally across the surface of the roll, with the lead or advance of the spiral relatively small and just sufficient to space the courses of the spiral properly after advancing 360 degrees around the surface of the roll.

Furthermore, I have found it preferable to utilize a shell 29 which is formed of relatively inexpensive material such as steel and thereafter form a separate sleeve having the fins Z6 machined on its outer surface and having an internal diameter adequate to permit its being slipped over the outer surface of the shell and securely locked thereto. This secondary sleeve can be manufactured of more expensive non-corrosive materials such as bronze and hence the cost of fabricating the new and improved breast roll is greatly reduced.

Nevertheless it is to be understood that the entire shell of the present invention can be cast as a single unit with the fins formed integrally on the outer surface during the casting operation.

In addition, an alternate form of the roll of the present invention would include a shell 20 having a spiral groove 29 machined therein with a continuous wire-like insert 30 of rectangular cross-section inserted in the groove. The spiral wire 30 is, of course, rigidly supported on the surface of the roll by the groove 29 and functions in the same manner as the integral fins 26.

In any case, where the spiral fin structure is employed, the lead or advance is so slight as to create an unobstructed, radially-extending, substantially annular passageway or groove which extends generally parallel to a plane passing radially through said roll at a right angle to the axis of the roll. The groove thus provides a plurality of passageways directly beneath the slice into which passageways the stock may be discharged from the slice. The stock thus may travel through the passageways along the outer surface of the shell 20 without being deflected upwardly and outwardly against the underside of the formed web as it is carried away by the Fourdrinier wire.

In addition, it is to be understood that the roll of the present invention may be employed with or without radially extending holes 31 passing therethrough and, if it is desired to use suction with the breast roll of the present invention such holes may be drilled or otherwise formed therein, as illustrated in FIGURE 4, and a suction box (not shown) may be disposed within the shell 20 directly beneath the slice 22 to create a vacuum which will assist in drawing the water through the wires into the annular grooves between the fins and thus eifect more rapid formation of the sheet on the wire 21.

Although the specific details of the construction of the fins 26 will depend upon the characteristics of the machine with which the roll is to be utilized, such as its speed, the diameter of the roll, the pressure of the stock of the wire, the tension in the wire and many other factors, I have found, by way of illustration, that in a breast roll having a twenty-five inch external diameter around the cover wire that fins which are approximately 1 in radial dimension (and thus create grooves which are 1 deep) and which are approximately /3 wide across the base (in axial dimension) and approximately .040" wide at the tip (in axial dimension) and spaced axially from each other approximately .4 have proven satisfactory in operation in a Fourdrinier machine producing light weight sanitary tissue at speed in excess of 2000 feet per minute.

It is to be understood however that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes hereof, and it is therefore desired that the present embodiments be considered in all respects as illustrative and therefore not restricted, reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

Having described my invention, what I claim as new and desire to protect by Letters Patent is the following:

1. In a Fourdrinier paper machine having a slice and a traveling forming wire for receiving paper stock from said slice, an improved breast roll supporting said wire beneath said slice, said breast roll comprising a substantially smooth surface cylindrical shell, a plurality of substantially annular fins around the periphery of said shell and spaced axially along the shell, and a cylindrical cover wire on said fins, said fins constituting the sole means for spacing said cover Wire from said shell, whereby a plurality of substantially unobstructed passageways are provided beneath said cover wire and extending transversely of said breast roll.

2. A paper forming machine as set forth in claim 1 5 6 wherein the fins in the breast roll are formed integrally 1,742,991 Heys Ian. 7, 1930 with said shell. 1,843,876 Kilberry Feb. 2, 1932 3. A paper forming machine as set forth in claim 1 1,928,286 Germanson Sept. 26, 1933 wherein the breast roll fins are formed by a continuous 2 1 4 Russell et 1, 11, 1941 helical ridge having a small angle of advance. 5 2418600 Ostertag et a]. APR 3 947 2,680,996 Brown June 15, 1954 References Cited in the file of this patent 2,803,172 Trotman Aug. 20, 1957 UNITED STATES PATENTS FOREIGN PATENTS 1.123. Schaanning 5, 1915 10 518,123 Great Britain Feb. 19, 1940 1,666,472 Seybold et a1. Apr. 17, 1928 

